The present invention relates to a twin-hull watercraft having two hulls which are disposed parallel to and spaced apart from each other, which are rigidly interconnected by means of tubular struts, which have propulsion and control units and which are adapted to accommodate between them a submersible craft, a diver work chamber or other operating equipment. A pilot's cab with a steering stand for the craft is rigidly connected with the hulls and disposed above the hulls, approximately in the longitudinal center plane. The hulls and the connections between the hulls and the pilot's cab being at least partly designed as pressure-resistant buoyancy bodies in that their weight is less than the weight of water displaced by them, and the hulls being designed as tight pressure vessels of the type of submarines and provided with cells that may be flooded and blown. The pilot's cab takes the form of a third pressure vessel which is equipped with pressure-resistant view ports and which can function as a buoyancy body in that its weight is less than the weight of water it displaces in the submerged condition. The twin-hull watercraft is weight-stable both in the fully submerged condition and also in the partially submerged condition, when the pilot's cab is still completely or partly above the mean waterline so that it can be used both as a form-stable surface-bound watercraft and as a weight-stable semisubmersible craft or a weight-stable submersible craft an egress to the outside for divers is provided on one of the connections between the hulls and/or the pilot's cab.
The above-described submersible catamaran distinguishes itself by its versatility in subsea service. Another advantageous property is to be seen in its large work radius in surface use and in the fact that as a semisubmersed or completely submersed craft it can be used under a wide variety of weather conditions.
It is the object of the present invention to improve such a submersible craft as regards its service properties, in particular as regards its driving qualities, work radius and suitability for heavy sea conditions.